Pulmonary resection for multi-drug resistant tuberculosis.

OBJECTIVES: Mycobacterium tuberculosis continues to be a major cause of morbidity and mortality throughout the world. Complacency by the medical profession and by patients has caused a new strain of Mycobacterium tuberculosis to emerge that is highly resistant to current antibiotics. The possibility of a new worldwide epidemic of drug-resistant Mycobacterium tuberculosis is of concern. Optimal therapy for patients infected with multi-drug resistant tuberculosis often requires surgical intervention to eradicate the infection. We report on our experience with pulmonary resection for multi-drug resistant tuberculosis. METHODS: During a 17-year period, 172 patients underwent 180 pulmonary resections. All patients had multi-drug resistant tuberculosis and had a minimum of 3 months of medical therapy before surgery. Muscle flaps were frequently used to avoid residual space and bronchial stump problems. RESULTS: During the study period, 98 lobectomies and 82 pneumonectomies were performed. Eight patients underwent multiple procedures. Operative mortality was 3.3% (6/180). Three patients died of respiratory failure, 2 patients died of a cerebrovascular accident, and 1 patient had a myocardial infarction. Late mortality was 6.8% (11/166). Significant morbidity was 12% (20/166). One half (91) of the patients had positive sputum at the time of surgery. After the operation, the sputum remained positive in only 4 (2%) patients. Mean length of follow-up was 7.6 years (range 4-204 months). CONCLUSIONS: Surgery remains an important adjunct to medical therapy for the treatment of multi-drug resistant Mycobacterium tuberculosis. In the setting of localized disease, persistent sputum positivity, or patient intolerance of medical therapy, pulmonary resection should be undertaken. Pulmonary resection for multi-drug resistant tuberculosis can be performed with acceptable operative morbidity and mortality.

Proinflammatory cytokines in heart disease.

Proinflammatory cytokines affect nearly all tissues and organ systems, and the vasculature is no exception. Although a considerable amount of research has focused on the role of the two most prominent proinflammatory cytokines, interleukin-1 (IL-1) and tumor necrosis factor (TNF), in the pathogenesis of sepsis and septic shock, the role of these and other cytokines in the pathogenesis of atherosclerotic lesions of the coronary artery, the acute ischemic event associated with myocardial infarction, the progression of myocardiopathies or the loss of myocardial function in congestive heart failure is a relatively recent discovery. Moreover, there has also been significant investigation of the cardioprotective effects of cytokines. Most of the attention has focused on the acute coronary syndromes and the myocardial suppression that takes place as a result of acute ischemia. The potential for anticytokine-based therapies in treating heart disease is great. Parenteral TNF-alpha neutralization and IL-1 receptor blockade are presently used to treat rheumatoid arthritis. Two orally effective agents, the IL-1beta-converting enzyme inhibitor and the mitogen-activating protein kinase p38 inhibitor, are currently being investigated in clinical trials.

Inhibition of caspase 1 reduces human myocardial ischemic dysfunction via inhibition of IL-18 and IL-1beta.

The proinflammatory cytokine IL-18 was investigated for its role in human myocardial function. An ischemia/reperfusion (I/R) model of suprafused human atrial myocardium was used to assess myocardial contractile force. Addition of IL-18 binding protein (IL-18BP), the constitutive inhibitor of IL-18 activity, to the perifusate during and after I/R resulted in improved contractile function after I/R from 35% of control to 76% with IL-18BP. IL-18BP treatment also preserved intracellular tissue creatine kinase levels (by 420%). Steady-state mRNA levels for IL-18 were elevated after I/R, and the concentration of IL-18 in myocardial homogenates was increased (control, 5.8 pg/mg vs. I/R, 26 pg/mg; P < 0.01). Active IL-18 requires cleavage of its precursor form by the IL-1beta-converting enzyme (caspase 1); inhibition of caspase 1 also attenuated the depression in contractile force after I/R (from 35% of control to 75.8% in treated atrial muscle; P < 0.01). Because caspase 1 also cleaves the precursor IL-1beta, IL-1 receptor blockade was accomplished by using the IL-1 receptor antagonist. IL-1 receptor antagonist added to the perifusate also resulted in a reduction of ischemia-induced contractile dysfunction. These studies demonstrate that endogenous IL-18 and IL-1beta play a significant role in I/R-induced human myocardial injury and that inhibition of caspase 1 reduces the processing of endogenous precursors of IL-18 and IL-1beta and thereby prevents ischemia-induced myocardial dysfunction.

Selective mitochondrial KATP channel opening controls human myocardial preconditioning: too much of a good thing?

BACKGROUND: Paradoxically, patients with noninsulin-dependent diabetes mellitus experience a higher cardiovascular mortality rate than patients with insulin-dependent diabetes mellitus. We have shown that K(ATP) channel inhibition, with oral sulfonylureas, prevents myocardial preconditioning and may explain the paradox of cardiovascular death in patients with noninsulin-dependent diabetes mellitus. Cardiac preconditioning is an attractive protective strategy against any elective ischemia/reperfusion (I/R) injury. The relationship between the K(ATP) channels and human myocardial preconditioning has not previously been elucidated. METHODS: Human atrial trabeculae were harvested, placed in organ baths, and paced (1 Hz). Developed force was recorded during simulated 37 degrees C I/R (30/45 or 45/60 minutes). Before I/R, trabeculae were treated transiently with a selective mitochondrial K(ATP) channel opener for 5 minutes, followed by a 10-minute washout, or were exposed to the channel opener throughout ischemia. Recovery of function is expressed as percentage of baseline developed force. Conserved creatine kinase activity (units per gram of wet tissue) was measured at the end of reperfusion as an indicator of cellular protection. RESULTS: Transient mitochondrial K(ATP) channel opening provided protection from both I/R insults. Surprisingly, there was no protection afforded by continuous mitochondrial K(ATP) channel opening. CONCLUSIONS: Transient selective mitochondrial K(ATP) channel opening protects both viability and function of human myocardium against I/R injury, although prolonged opening of the mitochondrial K(ATP) channel does not. These results reinforce the concept of preconditioning as a transient event that must be completed before the onset of ischemia.

Selective mitochondrial adenosine triphosphate-sensitive potassium channel activation is sufficient to precondition human myocardium.

OBJECTIVES: Recently, the mitochondrial adenosine triphosphate-sensitive potassium channel has been suggested to be the final common effector of myocardial preconditioning. The purpose of this study is to determine whether selective mitochondrial adenosine triphosphate-sensitive potassium channel activation alone can precondition human myocardium from an ischemia/reperfusion insult. METHODS: Isolated human right atrial trabeculae were placed in tissue baths, paced, and subjected to 30 minutes of normothermic hypoxia (ischemia) followed by 45 minutes of reoxygenation (reperfusion). Trabeculae were preconditioned with a selective mitochondrial adenosine triphosphate-sensitive potassium channel opener (diazoxide 30 micromol/L) or a nonselective purinergic agonist, adenosine (125 micromol/L), for 5 minutes (adenosine) followed by a 10-minute washout period. Developed force at end reperfusion (mean +/- standard error) was compared with baseline, and tissue creatine kinase and adenosine triphosphate levels were measured after ischemia/reperfusion. RESULTS: Trabeculae subjected to ischemia/reperfusion exhibited 30% +/- 2% of baseline developed force, whereas trabeculae subjected to selective adenosine triphosphate-sensitive potassium channel opening (diazoxide) and nonselective purinergic agonist (adenosine) recovered to 55% +/- 7% and 46% +/- 3% of baseline developed force, respectively. Tissue creatine kinase activity was preserved in both the diazoxide- and adenosine-treated trabeculae (5.4 +/- 12 and 5.4 +/- 14 micromol/L per gram wet tissue) compared with ischemia/reperfusion (1.8 +/- 0.2 U/mg wet tissue). Adenosine triphosphate levels at end reperfusion were also increased in the trabeculae treated with selective (diazoxide) and nonselective (adenosine) adenosine triphosphate-sensitive potassium channel opener (4.1 +/- 0.01 and 4. 4 +/- 0.2 micromol/L per gram wet tissue) compared with trabeculae subjected to ischemia/reperfusion (1.5 +/- 0.1 micromol/L per gram wet tissue). CONCLUSIONS: These results suggest that selective mitochondrial adenosine triphosphate-sensitive potassium channel activation preconditions human myocardium and the protection conferred is equal to that of adenosine preconditioning. Targeted openers of mitochondrial adenosine triphosphate- sensitive potassium channels promote constructive protection of myocellular energy levels, contractile function, and cellular viability in human myocardium after ischemia/reperfusion.

Chemokines as mediators of diseases related to surgical conditions.

Chemokines are important mediators of inflammation. Animal studies suggest that inhibition of chemokine action results in a decrease in inflammation. Novel anti-inflammatory agents directed against chemokines are now available. Surgeons are uniquely positioned to treat multiple chemokine-mediated diseases. In this article, we review the biology and nomenclature of chemokines as well as their role in neutrophil migration. Further, the potential role of chemokines in various diseases related to surgical conditions, including adult respiratory distress syndrome, atherosclerosis, inflammatory bowel disease, and solid organ rejection, is reviewed. Finally, the idea that chemokines could be targets for novel therapeutic agents is discussed.

Adenosine preconditioning reduces both pre and postischemic arrhythmias in human myocardium.

INTRODUCTION: Consistently, clinical series record supraventricular tachyarrhythmias in approximately 30% of patients following coronary artery bypass surgery (CABG). Ischemic preconditioning and adenosine preconditioning (Ado-PC) decrease postischemia/reperfusion (I/R) myocardial stunning, infarct size, and pharmacologically induced arrhythmias in all species including man. We hypothesized that adenosine preconditioning would decrease spontaneous pre- and postischemic atrial arrhythmias in human myocardium. The purposes of this study were to determine the effect of in vivo and in vitro Ado-PC on atrial arrhythmias. METHODS: Human atrial trabeculae were harvested from CABG patients, placed in organ baths, and paced (1 Hz). Developed force (DF) was recorded during simulated I/R (30/45 min). Prior to I/R, trabeculae were treated with Ado (125 microM) for 5 min (in vitro), or patients were treated with Ado (12 mg iv) 5 min (in vivo) prior to harvest of trabeculae. Contraction frequency >4 Hz (defined as atrial tachyarrhythmias) was recorded in all groups pre- and postischemia. RESULTS: Control trabeculae exhibited increased tachyarrhythmias pre- and postischemia. In vivo and in vitro Ado-PC suppressed both pre- and postischemic arrhythmias. CONCLUSIONS: Adenosine preconditioning suppresses the frequency of pre- and postischemic tachyarrhythmias against an ischemia/reperfusion insult in human myocardium. This antiarrhythmic effect occurs with both in vitro and in vivo administration of adenosine. Preconditioning with adenosine prior to elective ischemia/reperfusion is a promising strategy of reducing spontaneous atrial arrhythmias in patients undergoing myocardial revascularization.

Liposomal delivery of heat-shock protein 72 into the heart prevents endotoxin-induced myocardial contractile dysfunction.

BACKGROUND: The purposes of this study were to (1) determine whether functional heat-shock protein 72 (HSP-72) may be delivered into the heart, (2) determine whether HSP-72 itself is protective against endotoxin (lipopolysaccharide [LPS]-induced cardiodepression, and (3) compare relative protection and time courses required for protection for thermally induced HSP-72 versus liposomally introduced HSP-72. METHODS: HSP-72 was introduced (liposomal HSP-72) or induced (heat shock, 42 degrees C x 15 minutes, 24 hours before) in rat heart before LPS administration (0.5 mg/kg intraperitoneal or ex vivo coronary infusion). Western blot analysis for HSP-72 was used to confirm its expression. Left ventricular developed pressure (Langendorff) was used as an index of cardiac function. RESULTS: Direct intracoronary perfusion of liposomal HSP-72 delivered functioning HSP-72 into the myocardium. LPS induced cardiodepression; however, heat shock pretreatment abolished LPS-induced contractile dysfunction. A direct connection was found between HSP-72 and protection derived from liposomal transfer experiments that similarly reduced LPS-induced cardiodepression. CONCLUSIONS: (1) HSP-72 prevents LPS-induced myocardial contractile dysfunction, (2) liposomal transfer of HSP-72 into the myocardium provides the first direct mechanistic connection between myocardial HSP-72 and protection against LPS, (3) HSP-72 induction requires 24 hours and liposomal transfer of HSP-72 requires 90 minutes, and (4) HSP-72 may offer a clinically acceptable means of protecting the heart.

A plasmid vehicle suitable for the molecular cloning and characterization of mammalian promoters.

We have constructed a plasmid, pPSG4, that carries only the coding sequences for polyomavirus (Py) small, middle and truncated large T-antigens. A unique HindIII site allows the introduction of foreign promoters directly in front of viral coding sequences. The simian virus 40 (SV40) early and late, adenovirus-2 (Ad-2) major late and herpes simplex virus-1 (HSV-1) thymidine kinase (TK) promoters all confer on pPSG4 the ability to transform rat embryonic fibroblasts with high efficiency. Sequential deletion of the 72 bp repeats, the 21 bp repeats and the TATA box from the SV40 early region in pPSG4 produced a 50, then 30 and then a further 5 to 10-fold decrease in transformation efficiency, respectively. Thus pPSG4 is a convenient vector for the cloning and characterization of mammalian promoters.

Polyomavirus and simian virus 40 large T antigens bind to common DNA sequences.

The large T antigens of polyomavirus and simian virus 40 (SV40) recognize and bind to specific, noncoding DNA sequences which are located between the beginning of the early and late transcription units in their respective genomes. Each large T antigen binds to multiple sites within this intergenic DNA stretch. Polyomavirus large T antigen binds to at least two sites within its DNA, and SV40 large T antigen binds to three sites within SV40 DNA. Comparison of the DNA sequences which comprise the binding sites in polyomavirus DNA or those which make up the binding sites in SV40 DNA has led to recognition of a common sequence, -GAGGC-, which is repeated within each large-T-antigen-binding site. We tested the hypothesis that repeats of this pentanucleotide form the recognition-binding site for polyomavirus and SV40 large T antigen. This was accomplished by measuring the binding of each large T antigen to both polyomavirus and SV40 DNA and to synthetic DNA substrates which did or did not contain repeats of the -GAGGC- sequence. Polyomavirus large T antigen bound to specific fragments of SV40 DNA, and SV40 large T antigen bound with specificity to polyomavirus DNA. In each case, the DNA fragments bound by the heterologous large T antigen were the same as those bound by the homologous large T antigen. Moreover, polyomavirus and SV40 large T antigen only bound to synthetic DNA substrates which contained repeats of the pentameric sequence. This synthetic DNA also competed effectively with native polyomavirus or SV40 DNA as a substrate in binding reactions with one or the other large T antigen. These results led us to conclude that repeats of the -GAGGC- sequence form the recognition-binding site for both polyomavirus and SV40 large T antigen.

Collaborative interviewing: a family-centered approach to pediatric care.

The collaborative-consultative role of the social worker as a team member in primary-care pediatrics encourages a family-centered approach to health care. Planned, collaborative interviewing of patients and their families by social workers and medical or nursing staff early in a case appears to increase favorable outcomes of social work interventions, according to the study presented in this article.

Polyomavirus large T antigen binds independently to multiple, unique regions on the viral genome.

To map the polyomavirus large T antigen binding sites on the viral genome we employed a quantitative immunoassay. Defined, radiolabeled fragments of the viral genome were reacted with crude nuclear extracts prepared from lytically infected mouse 3T6 cells, and the fragments bound by large T antigen were immunoprecipitated with anti-T serum and Formalin-fixed Staphylococcus aureus. The immunoprecipitated DNA was then analyzed by gel electrophoresis and autoradiography. By the use of a variety of restriction endonuclease-generated fragments of wild-type and mutant viral DNAs, the region of high-affinity binding was localized to a 153-base-pair stretch between nucleotides 5292 and 152. At least two independent binding sites lie within this region, one upstream and the other downstream of the Bg/I site at nucleotide 87. One of the binding sites is located within sequences required in cis for DNA replication; the other overlaps the TATA box and cap sites of the early transcription unit. The two sites share a common sequence, A/TGAGGC-N4/5-A/TGAGGC, which may serve as the recognition sequence for large T antigen.

Homologous recombination between transfected DNAs.

An extensive analysis of the fate and structure of polyomavirus-plasmid recombinant molecules transfected into Rat-1 cells has revealed that the DNA often becomes integrated within transformed cell DNA in a head-to-tail tandem arrangement. This occurs independently of the replicative capacity of the transforming DNA and is facilitated by the use of large quantities of DNA during transfection. These observations have led us to suggest that head-to-tail tandems are formed by homologous recombination between transfected DNAs either before or after integration within cellular DNA. To test this hypothesis, we have measured the transforming activity of pairs of mutant, nontransforming, recombinant plasmid DNAs that carry different lesions in the transforming gene of polyomavirus. The results show that, although the individual mutant DNAs are incapable of transformation, transfection with pairs of mutant DNAs leads to the formation of transformed cells at high frequency. Moreover, there is a direct relationship between the distance between the lesions in pairs of mutant DNAs and their transforming activity. Finally, analyses of the structures of integrated recombinant plasmid DNAs and the viral proteins within independent transformed cells prove that recombination occurs between the mutant genomes to generate a wild-type transforming gene.

The impact of Vietnam service on heroin-addicted veterans.

Age-matched samples of Vietnam veterans and veterans who did not serve in Vietnam were surveyed at the time that they applied for treatment of heroin addiction. Vietnam veterans were more likely to have begun using heroin during their military service, and they were more likely to say that their service experiences had affected their use of drugs, usually citing relief of fear and tensions of war. Veterans who had not been in Vietnam were somewhat more likely to have begun using drugs after service, and generally indicated that their military experiences had not affected their drug use. When they did cite an effect of service, the factors usually indicated were boredom and a lack of meaningful activity. Attitudes toward narcotic use were negative in both groups, but significantly less so among Vietnam veterans. However, these attitudes did not relate to patterns of current or past drug use. Groups did not differ in the extent of or reasons for current illicit drug use, but non-Vietnam veterans reported more alcohol use. The Vietnam war was mentioned by one Vietnam veteran and by no non-Vietnam veterans as a reason for continuing narcotic use. Few other differences were found. Notably, typical treatment course over a 5-year follow-up period was similar in the two study groups.